/*
 * Copyright 2019 The Vitess Authors.

 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at

 *     http://www.apache.org/licenses/LICENSE-2.0

 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// statsd is a simple server for hosting test.go remote stats.
package main

import (
	"encoding/json"
	"io/ioutil"
	"log"
	"net/http"
	"strconv"
	"sync"
	"time"
)

var mu sync.Mutex

const statsFileName = "stats.json"

func main() {
	http.HandleFunc("/travis/stats", func(w http.ResponseWriter, r *http.Request) {
		if r.Method == "POST" {
			test := r.FormValue("test")
			result := r.FormValue("result")

			if test == "" || result == "" {
				return
			}

			switch result {
			case "pass":
				duration := r.FormValue("duration")
				if duration == "" {
					return
				}
				dur, err := time.ParseDuration(duration)
				if err != nil {
					return
				}
				testPassed(test, dur)
			case "fail":
				testFailed(test)
			case "flake":
				try := r.FormValue("try")
				if try == "" {
					return
				}
				i, err := strconv.ParseInt(try, 10, 64)
				if err != nil {
					return
				}
				testFlaked(test, int(i))
			}

			return
		}

		http.ServeFile(w, r, statsFileName)
	})

	http.ListenAndServe(":15123", nil)
}

type Stats struct {
	TestStats map[string]TestStats
}

type TestStats struct {
	Pass, Fail, Flake int
	PassTime          time.Duration
}

func testPassed(name string, passTime time.Duration) {
	updateTestStats(name, func(ts *TestStats) {
		totalTime := int64(ts.PassTime)*int64(ts.Pass) + int64(passTime)
		ts.Pass++
		ts.PassTime = time.Duration(totalTime / int64(ts.Pass))
	})
}

func testFailed(name string) {
	updateTestStats(name, func(ts *TestStats) {
		ts.Fail++
	})
}

func testFlaked(name string, try int) {
	updateTestStats(name, func(ts *TestStats) {
		ts.Flake += try - 1
	})
}

func updateTestStats(name string, update func(*TestStats)) {
	var stats Stats

	mu.Lock()
	defer mu.Unlock()

	data, err := ioutil.ReadFile(statsFileName)
	if err != nil {
		log.Print("Can't read stats file, starting new one.")
	} else {
		if err := json.Unmarshal(data, &stats); err != nil {
			log.Printf("Can't parse stats file: %v", err)
			return
		}
	}

	if stats.TestStats == nil {
		stats.TestStats = make(map[string]TestStats)
	}
	ts := stats.TestStats[name]
	update(&ts)
	stats.TestStats[name] = ts

	data, err = json.MarshalIndent(stats, "", "\t")
	if err != nil {
		log.Printf("Can't encode stats file: %v", err)
		return
	}
	if err := ioutil.WriteFile(statsFileName, data, 0644); err != nil {
		log.Printf("Can't write stats file: %v", err)
	}
}
